College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
J Appl Microbiol. 2024 Jul 2;135(7). doi: 10.1093/jambio/lxae120.
This study explores the potential of cadmium (Cd)-resistant bacteria, specifically Bacillus megaterium A14, to decrease Cd accumulation in peanuts, a crop susceptible to metal uptake from contaminated soils, by understanding the bacterium's impact on plant Cd absorption mechanisms.
Through pot experiments, we observed that A14 inoculation significantly increased peanut biomass under Cd stress conditions, primarily by immobilizing the metal and reducing its bioavailability. The bacterium effectively changed the distribution of Cd, with a notable 46.53% reduction in the exchangeable fraction, which in turn limited the expression of genes related to Cd transport in peanuts. Additionally, A14 enhanced the plant's antioxidant response, improving its tolerance to stress. Microbial analysis through 16S sequencing demonstrated that A14 inoculation altered the peanut rhizosphere, particularly by increasing populations of Firmicutes and Proteobacteria, which play crucial roles in soil remediation from heavy metals.
The A14 strain effectively counters Cd toxicity in peanuts, promoting growth through soil Cd sequestration, root barrier biofilm formation, antioxidant system enhancement, suppression of Cd transport genes, and facilitation of Cd-remediating microorganisms.
本研究旨在探讨耐镉细菌（特别是巨大芽孢杆菌 A14）通过了解该细菌对植物 Cd 吸收机制的影响，降低花生（一种易从受污染土壤中吸收金属的作物）中 Cd 积累的潜力。
通过盆栽实验，我们观察到 A14 接种在 Cd 胁迫条件下显著增加了花生的生物量，主要通过固定金属并降低其生物利用度。该细菌有效地改变了 Cd 的分布，可交换态分数显著减少了 46.53%，从而限制了花生中与 Cd 转运相关基因的表达。此外，A14 增强了植物的抗氧化反应，提高了其对胁迫的耐受性。通过 16S 测序进行的微生物分析表明，A14 接种改变了花生根际，特别是通过增加厚壁菌门和变形菌门的数量，这在重金属土壤修复中起着至关重要的作用。
A14 菌株有效地缓解了花生中的 Cd 毒性，通过土壤 Cd 螯合、根屏障生物膜形成、抗氧化系统增强、抑制 Cd 转运基因以及促进 Cd 修复微生物来促进生长。
